The cooking of vegetables, by definition, entails the use of heat to modify their chemical and physical properties. If we consider that most vegetables share these properties, it goes without saying that there are several science-based tips for improving the cooking process.
A question of water
Vegetables of this type consist largely of water. Just think that a zucchini contains as much as 93% water. Since much of the cooking process entails dehydrating the vegetable, the first rule is to eliminate as much of this water as possible beforehand. In this way, the cooked vegetable will taste less “boiled” than usual. To do this, you need to know a few tips.
The first tip is to cut the vegetable as much as possible, whether into fine slices, à la julienne or other shapes. Once cut, place the vegetables on plenty of absorbent kitchen paper. To speed up the dehydration process, you may also add salt to the cut vegetables. With this simple trick, you actually trigger quite a complex process. Salt increases the ionic concentration on the external walls of the vegetable cells and the water tends to leave the cell to rebalance it, thanks to a phenomenon known as “osmosis”. Apart from dehydration, osmosis contributes to making vegetables tender because the loss of water reduces cell pressure.
In the case of eggplants, there is an additional trick that comes in handy. After salting the sliced or diced aubergines, give them a quick whirl in the microwave oven: the water will evaporate more rapidly and the aubergines will not absorb too much oil, whichever way you decide to cook them.
In the case of vegetables containing less water, such as potatoes, cabbage and beetroot, our advice is to pre-cook them for a few minutes over a moderate heat, without adding anything else, and then use them in your favourite recipe. A quick cooking process helps break down the cell walls and “prepares” the vegetable more effectively for its final cooking process.
The microwave or traditional ovens are equally suitable even though, in the case of potatoes, a quick boil is even better since it eliminates part of the starch and enables you to obtain crisp slices and chips. If, on the other hand, you want to make mashed potatoes, you should NOT eliminate either starch or water.
The perfect consistency
If your problem consists in having to preserve the consistency of a vegetable after cooking (for example French beans, carrots and Brussels sprouts), the trick here consists in cooking them in a preheated oven at about 180°C for 6-7 minutes, preferably coated in a little oil or clarified butter. In fact, at this temperature, an enzyme called pectin methylesterase kicks in, causing the pectin contained in the cell wall to bond with the calcium ions contained in the vegetable. With what effect? Once your vegetables are cooked, they will remain beautifully intact and crisp.
How to Make a Salad of sandy vegetables
To put what you have learned into practice, I suggest trying out this easy and tasty recipe for a salad of "sandy" vegetables. Take whole Brussels sprouts, carrots, zucchini, violet potatoes and beetroots, slice, season with salt and pepper, and leave on absorbent paper for half an hour. Then, drizzle with olive oil, sprinkle with breadcrumbs and stir so that they stick to the vegetables. Finally, cook the mixture in a hot pan over a very high heat for 6 to 7 minutes.
You can eat the vegetables hot, but they are best enjoyed cold from the fridge, perhaps accompanied by good quality prosciutto.